Parabolic trough solar collector for fluid heating and photovoltaic cells

Abstract

A solar concentrating collector includes corrugated board parabolic support segments with flexible strips and side tabs over the cut edge to support a laminate with reflective coated film. The reflector assembly has supporting arms and pivots about a heat absorbing conduit secured to vertical extensions of adjacent stationary posts. Selected external surfaces are weatherproofed. The conduit includes vacuum insulators and means to isolate conduit from insulator expansion. Upper arms support pulleys and cable take-ups for continuous collector position changes. Cross members of the extended post secure the fixed conduit, and at a higher level, a programmable drive to rotate two cable capstans for cables that pivot two adjacent reflector assemblies. Other embodiments include triangular or square fluid conduits with planar surfaces for photovoltaic cells and a modified reflective surface to disperse solar rays into a band of reflected sunlight directed to photocell areas.

Description

BACKGROUND AND SUMMARY OF THE INVENTION[0001]The use of linear parabolic reflector troughs for concentrating solar rays on a heat collector pipe is well known. Prior collector systems for heating fluids to generate power depend from and use many of the same components as systems going back 40 or more years.[0002]Several current “state of the art” solar energy generating plants (SEGS) ranging from 30 to 320 megawatts are operating in the Mojave desert of California. The collectors include spaced parabolic truss supports extending transversely from about 6 to 18 ft wide. Collector systems heat fluids from 560 degrees to over 700 degrees F., and all use trusses extending outward from a pivoting central structure or tube, to support cast linear parabolic shaped mirrors to form the trough.[0003]Current parabolic mirror reflectors and trusses together with the attached absorber conduit are pivoted about a central structure or tube using hydraulic actuators and speed reduction gear boxes.[...

AI Technical Summary

Benefits of technology

"The patent describes a new solar energy generating system that uses linear parabolic reflector troughs to concentrate solar rays on a heat collector pipe. The system includes a simplified panel support and pivot system, as well as vacuum insulators to reduce heat loss and leakage. The system also uses a downwardly extending arm to suspend the reflector panel for pivoting about the absorber conduit, which simplifies the support system. The use of low-cost corrugated board and a cutting system allows for the production of parabolic segments in large quantities. The system can also include photovoltaic solar cells mounted on side planar surfaces to capture the dispersed solar rays. Overall, the invention offers a cost-effective and efficient way to generate solar energy."

Problems solved by technology

Current designs have inherent cost and maintenance problems which together with the cyclic nature of the sun (including cloudy days) prevents solar power generating plants from producing cost effective power available around the clock.

Aside from cost and operating differences, the combined cycle plant still had CO2 emissions and is subject to fossil fuel price fluctuations or supply disruptions.

Because of the gradient from ambient temperature to maximum, the difference in expansion of the glass tube and absorber pipe in current SEG designs requires an “expansion bellows” between sections of conduit and are prone to leakage and loss of vacuum.

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